Effects of Anesthetics on Neuromuscular Transmission and Somatic Reflexes

Abstract

Effects of various anesthetics on neuromuscular transmission and somatic reflexes were studied in unanesthetized, midcollicular decerebrate and spinal cats respectively. Diethyl ether was the only agent which significantly decreased the tibialis twitch response to indirect stimulation but an inspired concentration much higher than that required to produce areflexia was necessary. Cyclopropane, and to a lesser extent nitrous oxide and chloroform, increased the tibialis twitch response. It appears that, at least with cyclopropane, this response is a postsynaptic phenomenon distinct from its depressant action on the nervous system. All of the potent anesthetics tested, with the exception of methoxyflurane, abolished spinal (polysynaptic) and cephalic reflexes simultaneously. Methoxy-flurane depressed the spinal reflex earlier and at a lower inspired concentration.